The present invention relates to compositions and methods for supplementing or complementing natural central nervous system hormonal and neurotransmitter activity to optimize global brain function, particularly in disorders associated with memory impairment. More specifically, the present invention relates to a composition comprising phytoestrogens and an acetylcholinesterase inhibitor for use in treating, retarding, or preventing neurodegeneration and cognitive decline and dysfunction associated with Alzheimer""s disease (AD), aging, other related dementia disorders, and menopause.
The physiologic impact of estrogen deprivation, preceding and following the menopause, has a significant effect on the brain function and, hence, the quality of life for numerous women. A side variety of disorders may occur including, but not limited to, vasomotor instability with resulting hot flashes, disturbances in mood and affect, depression and irritability, spatial disorientation, and difficulty with verbal memory recall. Estrogen deprivation may also be an initiator or promotor of a series of biochemical abnormalities associated with the pathogenesis of Alzheimer""s disease, senile dementia, and related conditions, including central nervous system (CNS) arteriosclerotic disease (also known as stroke). Impairment of balance involving cerebellar dysfunction and other postural mechanisms predisposes older postmenopausal women to falls, resulting in hip fractures and its consequences.
An individual""s response to the menopausal transition depends on a number of variables, for example, genetic background, life-style factors (i.e., substance abuse, smoking), physical activity, response to chronologic aging, as well as the individual""s brain xe2x80x9cset-pointxe2x80x9d for estrogen. This, in turn, could depend on the distribution of beta and: alpha receptors in the brain and their affinity for either endogenous or exogenous estrogen.
A further manageable determinant of CNS dysfunction is the availability and reserve of the various CNS neurotransmitters. Senile dementia, especially Alzheimer""s disease is a major disease associated with aging. Although the exact mechanisms responsible for senile dementia and Alzheimer""s disease have not been elucidated, a growing body of evidence suggests that cholinergic neurons are essential for learning and memory processes [Bartus et al., Science 217:408 (1982); and Singh et al., Brain Research 644: 305 (1994)]. Alzheimer""s disease is strongly associated with decreased choline acetyltransferase (ChAT) activity and (loss of cholinergic neurons [New England Journal of medicine 313:7 (Jul. 4, 1985); and Kosik, Science 256:780 (1992)]. The number of patients suffering with Alzheimer""s disease and the costs associated with this disease are increasing dramatically with the increasing population of the elderly. About four million Americans (10% of the elderly at the age of 65 and 47% of the elderly at the age of 85 or higher) suffer with Alzheimer""s disease [Evans et al., JAMA 262:2251 (1989)]. The incidence of dementia and Alzheimer""s disease is reported to double every 5 years after the age of 65 [Jorm et al., Acta Psychiatr. Scand. 76:465 (1987)].
Currently, there is no cure for this devastating disease. Tremendous efforts have been undertaken to develop treatments for this disease. Treatment approaches which have been tested extensively include precursors for acetylcholine synthesis, cholinergic agonists, release enhancers and acetylcholinesterase (AChE) inhibitors. Various treatment approaches are shown below in Table 1.
Of these treatments, only AChE inhibitors like tacrine and physostigmine appear to be mildly effective in improving symptoms of Alzheimer""s disease. For example, in some patients, these inhibitors increased the levels of acetylcholine in the brain. However, the major limitation of AChE inhibitor treatment is that cognitive function is improved only in patients whose brains still have a sufficient number of cholinergic neurons to synthesize acetylcholine. This treatment approach is totally ineffective in patients whose brains have suffered a serious loss of cholinergic neurons. Moreover, this treatment is not able to retard the loss of cholinergic neurons. In addition, tacrine has also been shown to be toxic to the liver [Watkins et al., JAMA 271:992 (1994)], and produces other undesirable side effects as well (see Table 2 below).
The AChE inhibitor, physostigmine, has been found to exert mild beneficial effects on cognitive function in patients with Alzheimer""s disease. Unfortunately, the short half-life of physostigmine renders this compound ineffective for use in treating Alzheimer""s disease [Whitehouse, Acta Neurol. Scand. 149:42 (1993)].
Recently, a novel AChE inhibitor, Huperzine A, has been reported to have selective and long-term inhibition of brain AChE with few side effects, and appears to be an effective treatment for improving cognitive function associated with cholinergic deficiency in patients with Alzheimer""s disease [Tang, Acta Pharmacol. Sinica. 17:481(1996)].
Huperzine A (Hup A) was first isolated from Huperzia Serrata Trev and Chinese folk herb Qian Cheng Ta [Liu et al., Can J. Chem. 64:837 (1986)]. Hup A is a novel Lycopodium alkaloid [(5R, 9R, 11E)-5-amino-11-ethylidene-5,6,9,10-tetrahydro-7-methyl-5,9-methanocycloocta(b)pyridin2(1H)-one] as shown in FIG. 1. Hup A appears to be a much more potent and selective inhibitor of brain AChE than the other AChE inhibitors tested, and has few side effects [Tang, Acta Pharmacol. Sinica. 17:481 (1996)]. As shown below, Table 3 illustrates the in vivo anti-acetylcholinesterase activity of various AChE inhibitors in the blood and brain.
In vivo animal studies indicated that Hup A can exert inhibition of brain AChE much longer than physostigmine (360 min vs 60 min) [Tang, supra, (1996)]. In fact, Hup A is very specific against AChE as indicated by the IC50 values shown above in Table 3. In contrast, tacrine has a lower specificity for AChE, and also inhibits butyrylcholinesterase (BuChE) at an IC50 value comparable to AChE. Studies further revealed that Hup A inhibits AChE in the cerebral cortex and, more importantly, in the hippocampus where acetylcholine synthesis was markedly reduced in Alzheimer""s patients [Hallak and Giacobine, Neurochem. Res. 11:1037 (1986); and Tang, J., Neurosci. Res. 24:276 (1989)]. These results are illustrated in FIG. 2. In addition, Hup A appears to be effective in inhibiting AChE activity in the cerebral cortex, hippocampus, and other brain regions after chronic treatment in rats [Lagniere et al., Neuropharmacol. 30:763 (1991)]. These results are illustrated in FIG. 3.
The data collectively indicate that Hup A can be used to improve the symptoms of Alzheimer""s disease in patients with fewer peripheral side effects as compared to other AChE inhibitors. The major limitation of Hup A, however, is that it cannot retard neurogeneration associated with Alzheimer""s disease.
With respect to the use of hormone replacement therapy for treating Alzheimer""s disease, estrogen has been shown to reduce the incidence of Alzheimer""s disease and related dementias, relieve symptoms of Alzheimer""s disease, preserve cholinergic function, and improve cognitive function in postmenopausal women and in patients with Alzheimer""s disease [Sherwin, Ann. NY Acad. Sci. 743:213 (1994); and Paganini-Hill, Brit. J. Obstet. 103:80 (1996)]. This suggests that estrogen deficiency may be at least partially responsible for the neurodegeneration [Simpkins et al., Neurobiol. Aging 15: s195 (1994)]. This hypothesis is supported by the fact that estrogen deficiency results in decreased ChAT activity, and ChAT, BDNF, and NGF mRNAs, which can be reversed with an estrogen supplement [Luine, Exp. Neurol. 89:484 (1985); Gibbs et al., Exp. Neurol. 129:70 (1994); Singh et al., Abstr. Soc. Neurosci. 19:1254 (1993); Singh et al., Brain Res. 644:304 (1994); Singh et al., Endocrinol. 136:2320 (1995); and Sohrabji et al., Proc. Natl. Acad. Sci. USA 92:11110 (1995)].
Estrogen replacement in postmenopausal women appears to be the treatment of choice for reducing the incidence of dementia including Alzheimer""s disease and improving the symptoms of Alzheimer""s disease. However, traditional estrogen replacement therapy significantly increases the risk of breast and uterine cancers especially after long-term use, and also has intolerable side effects (e.g. menstrual bleeding, mood swings, and bloating) for some women [Levi et al., Eur. J. Cancer. 29A:1445 (1993); and Bergkvist and Persson, Drug Safety 15:360 (1996)]. These side effects may be nearly impossible to tolerate in women with dementia. Moreover, cancer risks have deterred widespread acceptance and use of estrogen replacement therapy as a treatment for various disorders associated with aging (including cognitive deficiency and dementia).
Soy phytoestrogens have also been studied to evaluate their effects on cognition. Soy phytoestrogens are plant analogs of estrogen, and have estrogen-like activity in some classical estrogen-responsive tissues. Since dietary intake of soy phytoestrogens is much higher in Japan and other Asian countries than in the U.S. and other Western countries, it has been speculated that soy phytoestrogens may account for the lower incidence of cardiovascular disease, breast cancer, and Alzheimer""s disease in these Asian countries relative to the U.S. and other Western countries. Indeed, studies have demonstrated that soy phytoestrogens have no estrogenic effects on the breast and uterus [Foth and Cline, Am. J. Clin. Nutr. 68:14135(1998)], but retain the beneficial estrogenic effects on the cardiovascular system [Anthony et al., Arterio. Thrombo. Vasc. Biol., 17:2524 (1997)].
Co-inventors of the present invention have examined the effects of soy phytoestrogens on brain biomarkers, ChAT and brain-derived neurotrophic factor (BDNF). ChAT and BDNF are essential for normal cognitive function in retired breeder rats. Experimental results indicated that soy phytoestrogens up-regulate ChAT and BDNF mRNAs in the frontal cortex of retired breeder female rats just as estradiol does. Results suggest that soy phytoestrogens act as estrogen agonists in preserving the integrity and function of cholinergic neurons in the cerebral cortex, and may be used as an estradiol substitute in postmenopausal women to preserve cognitive function and in Alzheimer""s patients to improve symptoms and retard further neurodegeneration [Pan et al., Proc Soc Exp Biol Med 221(2):118 (1999) and Pan et al., Neurosci Lett 261(1-2):17 (1999)].
Phytoestrogens are natural components of plants that mimic estrogen in animal tissues. For instance, some plants can induce estrus in animals largely due to the presence of phytoestrogens. To date, more than 300 plants have been identified that possess estrogenic activity. Phytoestrogens are classified into two chemical categories (coumestans and isoflavones), and have 15 carbon structures similar to the 17-carbon structure of estradiol shown below. 
Legumes and grains are among food sources which have the highest content of isoflavones. For example, the content of isoflavones in soybeans ranges from approximately 0.5 to 3 mg per gram of soy protein. Dietary phytoestrogens appear to be readily absorbed in humans. Genistein, daidzein, and equol are the main isoflavones absorbed from the intestine, and are the metabolic products (of dietary isoflavones) generated by colonic bacteria which remove a glycoside moiety [King et al., J. Nutr. 126:176 (1997); and Sfakianos et al., J. Nutr. 127:1260 (1997)]. Dietary intake of soy phytoestrogens is much higher in Japan than in the U.S. and other Western countries. As a result, Japanese have a much higher blood concentration of phytoestrogens than adults in Western countries. Further, epidemiological studies show that the incidence of Alzheimer""s disease in the elderly is lower in Japan than in the U.S. However, Japanese-Americans, who adopted a U.S. dietary style, were found to have developed Alzheimer""s disease at a rate comparable to Americans [Graves et al., Am. J. Epidemiol. 144:760 (1996)]. These data suggest that high intake of dietary phytoestrogens may play an important role in reducing the incidence of Alzheimer""s disease.
The mechanisms by which soy phytoestrogens, as well as estrogens, exert beneficial effects on brain cognitive function remain to be elucidated. Based on data collected by co-inventors of the present invention and indirect data concerning possible actions of soy phytoestrogens in mammalian cells by other researchers, the following mechanisms may account for the beneficial effects of soy phytoestrogens on brain cognition:
1. Soy phytoestrogens may act as estrogen agonists and exert protective effects on neurons including cholinergic neurons via estrogen receptors xcex1 and xcex2 (ER xcex1 and ER xcex2). Isoflavones appear to be weak estrogens in vivo and in vitro. Genistein""s affinity for ER xcex1 is about 20 times lower than that of estradiol. However, genistein""s affinity for ER xcex2 is just 3 times lower than that of estradiol [Kuiper et al., Endocrinol. 138:863, (1997)]. Experimental data by co-inventors of the present invention demonstrates that both estradiol and soy phytoestrogens significantly up-regulate the levels of the mRNAs of ChAT, a reliable index of cholinergic function, and BDNF in the frontal cortex of retired breeder rats (see FIG. 4). [Pan et al., Proc Soc Exp Biol Med 221(2):118 (1999) and Pan et al., Neurosci Lett 261(1-2):17 (1999)]. Further, the co-inventors have further demonstrated that both ER xcex1 and ER xcex2 mRNAs are present in the frontal cortex and hippocampus of retired breeder rats. These data support the hypothesis that soy phytoestrogens as well as estradiol may directly interact with ER xcex1 and ER xcex2 to preserve cholinergic function in these regions [Pan et al., Proc Soc Exp Biol Med 221(2):118 (1999)].
2. Non-estrogen receptor-mediated mechanisms: Soy phytoestrogens may act as antioxidants [Ruiz-Larrea et al., Free Radic Res 26:63 (1997)] to protect neurons against oxidative damages and retard the neurodegeneration caused by oxidative damage. In addition, soy phytoestrogens may improve cerebral blood circulation and, therefore, improve oxygen and nutrient supply to cells in the brain.
A. Introduction
A growing body of evidence shows that postmenopausal estrogen replacement therapy (ERT) appears to be effective in reducing the risk of cardiovascular diseases, osteoporosis, and senile dementia (especially AD) [Clarkson et al., Brit. J. Obstet. Gynaecol. 103:53, (1996); Ettinger, Obstet. Gynecol. 72:12S, (1988); Knopp, Obstet. Gynecol. 72:23S, (1988); Paganini-Hill, Brit. J. Obstet. Gynaecol. 103:80 (1996); Speroff et al., JAMA 276:1397 (1996); Sullivan, Brit. J. Obstet. Gynaecol. 103:59 (1996); and Tang et al., Lancet 348:429 (1996)]. The mechanisms by which estrogen preserves brain cognition are not known. Evidence suggests that estrogen may preserve brain cognition via a number of possible mechanisms including the maintenance of cholinergic function and interaction with neurotrophic factors, especially neurotrophic growth factor (NGF) and BDNF [Gibbs et al., Exp. Neurol. 129:70 (1994); Singh et al., Abstr. Soc. Neurosci. 19:1254 (1993); Singh et al., Endocrinol. 136:2320, (1995); and Sohrabji et al., Proc. Natl. Acad. Sci. USA 92:11110 (1995)]. Unfortunately, traditional estrogen replacement can significantly increase the risk of breast and uterine cancers, and has intolerable side effects for some women [Levi et al., Eur. J. Cancer. 29A: 1445 (1993); and Bergkvist and Persson, Drug Safety 15:360 (1996)].
It is conceivable that any compounds which can maintain normal levels of ChAT and BDNF in cholinergic neurons the basal forebrain (such as septum) and their target brain tissues (cerebral cortex and hippocampus) may reduce or even prevent loss of cholinergic neurons, and can be used in postmenopausal women to prevent Alzheimer""s disease or to relieve the symptoms of Alzheimer""s disease. It is of great importance to find compounds which retain the beneficial effects of estrogen on the brain cognitive function and Alzheimer""s disease, but which do not have cancer-promoting effects in the breast and uterus, and other adverse effects. Soy phytoestrogens are among the promising candidates for this purpose, because they have no estrogenic effects on breast and uterus, but retain the beneficial estrogenic effects on cardiovascular system [Clarkson et al., Trends Endocrinol. Metab. 6: 11 (1995)]. To date, their effect on brain cognitive function and Alzheimer""s disease has not been investigated.
The following study was designed to examine the effects of soy phytoestrogens and 17-xcex2 estradiol on ChAT and BDNF mRNAs in the frontal cortex and hippocampus of ovariectomized retired breeder rats.
B. Materials and Methods
Animalsxe2x80x9415 rats (retired breeders weighing 300-360g) were purchased from Harlan Sprague Dawley, Inc. The rats were housed in separate cages, and were maintained on a 12:12 hour light/dark cycle with access to food and water ad libitum. All procedures performed on the animals were approved by the Animal Care and Use Committee at Wake Forest University School of Medicine.
Experimental procedurexe2x80x94Rats were randomized into three groups based on body weight. Three days after a bilateral ovariectomy, animals in groups 1, 2 and 3 were fed a control diet [Ctl diet, a casein/lactalbumin-based diet], a control diet supplemented with estradiol [E2 diet, 17xcex2 estradiol (Estrace(trademark)) purchased from Mead Johnson Laboratory] equivalent to a woman""s dose of 2 mg/day, or a control diet supplemented with a soy phytoestrogen extract [SPE diet, soy phytoestrogens kindly provided by Protein Technologies International, St. Louis, Mo.] equivalent to a woman""s dose of 150 mg total isoflavones/day, respectively. At the end of the eight-week treatment, the animals were euthanized with pentobarbital (100 mg/kg). Blood samples were collected by cardiac puncture at necropsy, and serum samples were used to determine estradiol and phytoestrogen levels. Brains were removed from the skull immediately after decapitation. Frontal cortex and hippocampus were dissected and frozen in liquid nitrogen. The frozen samples were then stored at xe2x88x9270xc2x0 C. until RNA isolation.
RNA isolationxe2x80x94Total cellular RNA was isolated from tissues with TriZol Reagent (GIBCOL, BRL). The relative purity of isolated RNA was assessed spectrophotometrically, and the ratio of A260 nm to A280 nm exceeded 1.9 for all prep acetylcholinesterase inhibitor arations.
RT-PCRxe2x80x94RT-PCR was employed to detect the presence of BDNF and ChAT mRNAs in the brain samples, and to synthesize specific cDNA probes for Northern analysis of rat ChAT, BDNF and xcex2-actin mRNAs. The primers used for ChAT, BDNF, and xcex2-actin were selected in accordance with protocol from previous studies [Strauss et al., Neurosci. Lett. 168:193 (1994)]. The RT-PCR protocol was modified from the procedure reported by Pan et al., Biochem. Biophy. Acta 1307:233 (1996)] by optimizing the annealing temperature for these primer pairs (65xc2x0 C.) and shortening the extension cycle time to 40 s. The modified PCR cycle conditions were 94xc2x0 C. for 1 min, 65xc2x0 C. for 1 min, and 72xc2x0 C. for 40 s, followed by a final extension at 72xc2x0 C. for 3 minutes. The specificity of the RT-PCR products was confirmed by sequencing analysis. The nucleotide sequences were 100% identical to those of published cDNA or mRNA sequences for ChAT, BDNF and xcex2-actin.
Northern Analysisxe2x80x94RNA samples (30 ug) prepared from the frontal cortex or hippocampus were separated on 1.0% agarose gel by electrophoresis, then transferred to nylon membranes in 10xc3x97SSC at room temperature overnight (18 hours). The membranes were then subjected to a UV-cross linker and prehybridized at 42xc2x0 C. for 4 hours. Finally, the membranes were incubated with ChAT, BDNF or xcex2-actin-specific PCR probes at 42xc2x0 C. for 20 hours. After incubation, the washed membranes were subjected to phosphoimager analysis. The optical density reading of ChAT or BDNF was normalized by the optical density reading of xcex2-actin, which was obtained by reprobing the same membrane with xcex2-actin-specific probe.
C. Results
Both BDNF and ChAT mRNAs were present in the frontal cortex and hippocampus regardless of treatment as indicated by the specific RT-PCR products. Both estrogen and phytoestrogens upregulated ChAT and BDNF mRNA levels in the frontal cortex of the retired breeder rats (see FIG. 4). ChAT and BDNF mRNA levels were comparable among OVX, E2, and soy phytoestrogen groups in the hippocampus of the retired rats.
D. Discussion
RT-PCR analysis indicates that ChAT mRNA is present in the frontal cortex and hippocampus of retired breeder rats, which confirms previous reports of the presence of ChAT mRNA in these two regions [Cavicchioli et al., Brain Res. Mol. Brain Res. 9:319 (1991); Lauterbom et al., Brain Res. Mol. Brain Res. 17:59 (1993)]. Northern analysis of total RNA isolated from the frontal cortex and hippocampus of both young and retired breeder rats revealed a 4.4 kb band, which is consistent with the reported size of ChAT mRNA in rats [Ishii et al., Brain Res. Mol. Brain Res. 7:151 (1990)]. Phosphoimager analysis of Northern blots indicates that ChAT mRNA levels were significantly higher in the frontal cortex of E2 and SBE groups as compared to the OVX controls, and were comparable in the hippocampus among treatments in the retired breeder rats. The data suggest that ChAT mRNA in different regions of the brain is not equally susceptible to estrogen deficiency. This theory is supported by previous experimental results which demonstrated that long-term ovariectomy reduced ChAT activity in the frontal cortex of rats by 50%, but had little impact on ChAT activity in the hippocampus [Singh et al., Brain Res. 644:305 (1994)]. The Singh et al. results suggest that the frontal cortex is more susceptible to estrogen deficiency than the hippocampus.
The co-inventors of the present invention have demonstrated that soy phytoestrogens are very effective in up-regulating ChAT mRNA in the frontal cortex of retired breeder rats under conditions of estrogen deficiency, suggesting that soy phytoestrogens may have a similar effect as estrogen in regulating ChAT mRNA. The data further indicated that both estradiol and soy phytoestrogens up-regulated BDNF mRNA levels in the frontal cortex of retired breeder rats, but had little impact on the BDNF mRNA levels in the hippocampus of retired breeder rats. This data is consistent with previous reports that BDNF mRNA in the cerebral cortex was regulated by estrogen status, and that estrogen replacement restored BDNF mRNA to normal levels in ovariectomized rats [Singh et al., Endocrinol. 136:2320 (1995)].
The mechanisms by which estrogen exerts its protective effect on brain cognitive function have yet to be determined. It is plausible that estrogen, as a member of the steroid hormone family, may function at least partially through its receptors [Brown, Breast Cancer 8:101 (1994)]. Two subtypes of estrogen receptors (ER xcex1 and ER xcex2) have been reported [Green et al., Nature 320:134 (1986); Kuiper et al., Proc. Natl. Acad. Sci. USA 93:5925 (1996); and Mosselman et al., FEBS 392:49 (1996)]. ER xcex2 is reported to be the major subtype of ER in some regions of the brain [Kuiper et al., Endocrinol. 138: 863 (1997)]. Interestingly, genistein""s binding affinity to ER xcex2 is only three times lower than the potent 17 xcex2-estradiol [Kuiper et al., Endocrinol. 138:863 (1997)], which provides a molecular basis for soy phytoestrogens, or at least genistein, to interact with ER xcex2 and induce estrogenic effects. In addition, Sohrabji et al. [Proc. Natl. Acad. Sci. 92:11110 (1995)] demonstrated that the BDNF gene contained a putative estrogen response element. These data suggest that estrogen and soy phytoestrogens may directly regulate expression of the BDNF gene in the brain. Overall, the data indicate that soy phytoestrogens have similar effects as estrogen in preserving ChAT and BDNF mRNA levels in the frontal cortex of retired breeder rats.
Currently, there is no known cure for neurodegeneration and cognitive decline and dysfunction associated with Alzheimer""s disease, aging, other related dementia disorders, and estrogen deficiency related conditions. Although different treatment approaches have been used as described herein, each has disadvantages which limit their effectiveness and/or produce serious side effects. Thus, there remains a need for a therapeutic which is effective in treating, retarding, and/or preventing neurodegeneration and cognitive decline and dysfunction associated with Alzheimer""s disease and other related dementia disorders.
The present invention is directed to compositions and methods for treating, retarding, or preventing neurodegeneration and cognitive decline and dysfunction, particularly in disorders associated with memory impairment. The co-inventors of the present invention recognize the benefits of three compounds, phytoestrogens, mammalian estrogens, and acetylcholinesterase inhibitors, in combination to reduce or prevent loss of cholinergic neurons and to improve cognitive function and memory in mammals. The compositions of the present invention are suitable for use in treating those individuals with or at risk of developing Alzheimer""s disease, aging associated cognitive disorder (i.e., age associated memory impairment), other dementia related disorders, benign senescent forgetfulness, mild cognitive disorder, and estrogen deficiency related conditions. Preferably, those individuals include normal cycling pre-perimenopausal women, menopausal women, post-menopausal women, and men with aging related cognitive disorders. As an additional benefit, the present compositions overcome the disadvantages associated with current estrogen replacement therapies. Further, the synergism between the three compounds allows for a more effective lower dose therapy with fewer side effects as compared to other known therapeutics.
Given the numerous processes and functions of brain-regulated activities, the present invention seeks to provide both a specific therapeutic (memory) and a more general approach to mental well-being. In this regard, a pharmaceutical composition for administration to mammals is disclosed, comprising a combination of at least one mammalian estrogen and at least one acetylcholinesterase inhibitor in an amount sufficient to enhance memory and concentration in mammals. Further, a composition for enhancing memory and concentration is disclosed, which comprises a combination of at least one phytoestrogen and at least one acetylcholinesterase inhibitor, or any derivative, analog, or metabolite of the phytoestrogen and the acetylcholinesterase inhibitor, or any combination thereof. The composition includes dietary supplements, nutraceuticals, and food additives. It is contemplated that the pharmaceutical composition and the dietary supplement can be used to improve cognitive function, particularly in disorders associated with memory impairment such as Alzheimer""s disease, aging, other dementia related disorders, and estrogen deficiency related conditions.
In one aspect of the present invention, the composition comprises a combination of at least one phytoestrogen and at least one acetylcholinesterase inhibitor, or any derivative, analog, or metabolite of the phytoestrogen and the acetylcholinesterase inhibitor, or any combination thereof. The phytoestrogen is an isoflavone, coumestan, lignan, or any combination thereof. The phytoestrogenic isoflavone is selected from at least one of genistein, daidzein, biochanin A, formononetin, glycitein, the natural glycosides, or metabolites thereof. The phytoestrogen is derived from soy, clover, legumes, kudzu root, oilseeds, or any other phytoestrogen containing plant, or chemically synthesized. The acetylcholinesterase inhibitor is selected from at least one of the following: lycopodium alkaloids (i.e, Huperzine A and Huperzine B), piperidine-based inhibitors (i.e, Donepezil), carbamate-based inhibitors (i.e., Physostigmine, ENA-713 (Exelon or rivastigmine, a phenylcarbamate derivative), eptastigmine)), acridine-based inhibitors (Tacrine), alkaloids of the common snowdrop (i.e., Galanthamine), organophosphate cholinesterase inhibitors (i.e., Metrifonate, 2,2-dimethyldichlorovinyl phosphate (DDVP), hybrid of Huperzine A and Tacrine (i.e., Huperzine X) or any derivative, analog, metabolite or combination thereof. The composition includes about 0.5 mg to about 1000 mg phytoestrogen and about 0.01 mg to about 150 mg acetylcholinesterase inhibitor.
In another aspect, the present invention is a composition comprising a combination of at least one mammalian estrogen and at least one acetylcholinesterase inhibitor, or any derivative, analog, or metabolite of the mammalian estrogen and the acetylcholinesterase inhibitor, or any combination thereof. The mammalian estrogen is selected from the group consisting of estradiol, conjugated equine estrogens (CEE), any active estrogenic ingredients of CEE, estrone, estriol, esterified estrogens, and any derivative, analog, or metabolite of the mammalian estrogen. The estradiol is 17-xcex2 estradiol, estradiol valerate, ethinyl estradiol, or any other estradiol derivative, analog, or metabolite thereof. The composition includes about 0.2 mg to about 2 mg mammalian estrogen and about 0.01 mg to about 150 mg acetylcholinesterase inhibitor.
In another aspect of the invention, the composition comprises a combination of at least one phytoestrogen, at least one mammalian estrogen, and at least one acetylcholinesterase inhibitor, or any derivative, analog, or metabolite of the phytoestrogen, mammalian estrogen and the acetylcholinesterase inhibitor, or any combination thereof. The composition includes about 0.01 mg to about 1000 mg phytoestrogen, about 0.2 mg to about 2 mg mammalian estrogen, and about 0.01 mg to about 150 mg acetylcholinesterase inhibitor.
In another aspect of the present invention, a method is disclosed for treating, retarding or preventing memory impairment in mammals, comprising co-administering a combination of at least one phytoestrogen and at least one acetylcholinesterase inhibitor, or any derivative, analog or metabolite of the phytoestrogen and the acetylcholinesterase inhibitor, or any combination thereof in a therapeutically effective amount. The combination may further include at least one mammalian estrogen in a therapeutically effective amount for co-administration. Alternatively for administration, the combination can include at least one mammalian estrogen and at least one acetylcholinesterase inhibitor.
Any of compositions of the present invention may be prepared in a dosage form selected from the group consisting of a pill, capsule, tablet, powder, beverage, suspension, emulsion, syrup, solution, patch, gel, and the like. For administration purposes, the compositions may further include pharmaceutically acceptable carriers, diluents, stablizers, solubilizers, lubricants, binders and the like or excipients thereof
The term xe2x80x9cestrogen deficiency related conditionxe2x80x9d is used to refer to conditions associated with menopause, the surgical removal of the ovaries, and ovary dysfunction.
The term xe2x80x9ctherapeutically effective amountxe2x80x9d as used herein is defined as the dose which provides effective treatment or prevention for mammals, in particular humans, for the conditions, disorders, and diseases described herein.
The proceeding and further objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention.